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      <title>微服务之间的通信 - 交互式测验</title>
      <style>
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        .quiz-body {
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        .option-item {
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          border-radius: 8px;
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        .option-item.selected {
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            border-color: #4a90e2;
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        .quiz-footer {
          padding: 20px 30px;
          display: flex;
          justify-content: space-between; /* 将按钮分布在两侧 */
          align-items: center;
          min-height: 65px; /* Reserve space */
        }

        .nav-btn {
          background-color: #4a90e2;
          color: white;
          border: none;
          border-radius: 8px;
          padding: 10px 20px;
          font-size: 16px;
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          cursor: pointer;
          transition: background-color 0.2s ease, transform 0.2s ease;
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        .nav-btn:hover {
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        .nav-btn:disabled {
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        .result-box {
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        .result-box.correct {
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        .source-text {
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            font-size: 14px;
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        .final-score-container h2 {
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        .score-card {
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            border-radius: 12px;
            padding: 20px;
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            border: 1px solid #e9ecef;
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            font-size: 16px;
            font-weight: 500;
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            font-size: 16px;
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            font-size: 15px;
            line-height: 1.6;
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        }
      </style>
    </head>
    <body>
      <div class="main-wrapper">
          <div class="quiz-container">
            <div class="quiz-header">
              <h1>微服务之间的通信 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
            <div id="quiz-content">
                <div class="quiz-body">
                    <div class="progress-bar">
                        <div id="progress-indicator"></div>
                    </div>
                    <div id="question-container">
                      <p id="question-text"></p>
                      <ul class="options-list" id="options-list"></ul>
                    </div>
                    <div id="result-container"></div>
                    <div id="hint-container" class="hint-container"></div>
                </div>
                <div class="quiz-footer" id="quiz-footer">
                  <button id="prev-btn" class="nav-btn">上一题</button>
                  <button id="hint-btn" class="nav-btn" style="background-color: #ffc107; color: #333; box-shadow: 0 4px 12px rgba(255,193,7,0.3);">提示</button>
                  <button id="next-btn" class="nav-btn">下一题</button>
                </div>
            </div>
          </div>
      </div>

      <script>
        const quizData = [
  {
    "question": "在大规模微服务架构中，过度依赖同步通信可能导致什么主要问题？",
    "options": [
      "实现逻辑比异步通信更复杂",
      "服务耦合度高，单个服务故障可能引发连锁反应，即“雪崩效应”",
      "无法满足需要即时响应的业务场景",
      "必须引入消息队列等额外的中间件"
    ],
    "correctAnswerIndex": 1,
    "explanation": "同步通信要求调用方必须等待被调用方返回结果，这导致了服务间的强依赖。在一个长调用链中，如果任何一个服务变慢或失败，都会阻塞上游的所有服务，最终可能导致整个系统的大面积故障，这就是所谓的“雪崩效应”。",
    "source": "文档中「同步通信的优缺点」部分",
    "hint": "文档中提到了当请求链过长时，同步通信可能导致的一种严重后果。"
  },
  {
    "question": "与传统的基于HTTP/1.1的REST API相比，gRPC在微服务通信中的一个关键优势是什么？",
    "options": [
      "具有更好的浏览器兼容性和人类可读性",
      "调试过程更简单，可以使用浏览器直接测试",
      "基于HTTP/2和Protocol Buffers二进制序列化，性能更高、数据传输开销更小",
      "无需预先定义接口，开发更加灵活"
    ],
    "correctAnswerIndex": 2,
    "explanation": "gRPC使用HTTP/2协议，支持多路复用和流式传输，性能优于HTTP/1.1。同时，它采用Protocol Buffers作为默认的序列化协议，这是一种高效的二进制格式，相比于REST常用的JSON文本格式，数据量更小，解析速度更快，因此整体性能优势明显。",
    "source": "文档中「同步通信方式」下的「2. gRPC」部分",
    "hint": "请思考文本格式（如JSON）与二进制格式在传输效率和解析速度上的根本差异。"
  },
  {
    "question": "在一个电商系统中，用户下单成功后，系统需要触发库存扣减、发送通知邮件和更新用户积分。为什么采用异步通信（如事件驱动或消息队列）是处理此类场景的最佳实践？",
    "options": [
      "因为同步通信无法保证数据的一致性",
      "因为它能将核心流程（下单）与非核心流程（发邮件、加积分）解耦，提高系统的整体响应速度和容错性",
      "因为异步通信的实现成本远低于同步通信",
      "因为它能确保所有操作（扣库存、发邮件、加积分）都成功后才向用户返回成功信息"
    ],
    "correctAnswerIndex": 1,
    "explanation": "采用异步通信，下单服务在完成核心操作后可以立即响应用户，而将扣减库存、发送邮件等后续操作作为事件或消息发送出去。这样，即使某个下游服务（如邮件服务）暂时不可用，也不会影响用户下单的主流程，从而实现了服务解耦，增强了系统的健壮性和用户体验。",
    "source": "文档中「异步通信方式」下的「1. 消息队列（Message Queue）」和「2. 事件驱动架构」部分",
    "hint": "如果邮件发送服务暂时宕机，是否应该阻止用户成功下单？思考这个问题将有助于你找到答案。"
  },
  {
    "question": "当微服务内部通信对性能和网络带宽有极高要求时，文档推荐使用下列哪种“协议+序列化”组合？",
    "options": [
      "HTTP + JSON",
      "gRPC + Protobuf",
      "SOAP + XML",
      "HTTP + XML"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档明确指出，“gRPC + Protobuf”是高性能微服务间通信的首选。gRPC基于HTTP/2，性能优越，而Protobuf是高效的二进制序列化格式，两者结合能够最大限度地降低网络延迟和数据传输量，非常适合性能敏感的内部服务调用场景。",
    "source": "文档中「通信协议与序列化的结合」部分",
    "hint": "文档中明确指出了一个组合是“高性能微服务间通信的首选”。"
  },
  {
    "question": "根据文档，在“客户端发现模式”中，服务消费者（Client）需要承担哪些核心职责？",
    "options": [
      "将请求发送给一个固定的API网关进行转发",
      "直接向服务注册表查询可用服务的地址列表，并自行执行负载均衡策略",
      "依赖DNS服务器解析服务名到IP地址",
      "在配置文件中硬编码所有依赖服务的地址"
    ],
    "correctAnswerIndex": 1,
    "explanation": "在客户端发现模式中，客户端（服务消费者）自身集成了服务发现的逻辑。它会主动向服务注册中心（如Eureka）拉取服务提供者的实例列表，然后根据内置的负载均衡算法（如轮询、随机）选择一个实例发起调用。API网关转发属于服务端发现模式。",
    "source": "文档中「通信中的服务发现」下的「2.1 客户端发现模式」部分",
    "hint": "在这种模式下，客户端变得“更智能”，它需要自己决定该调用哪个服务实例。"
  },
  {
    "question": "在微服务安全认证中，使用JWT（JSON Web Token）的主要优势是什么？",
    "options": [
      "它能对所有传输数据进行端到端加密，比TLS更安全",
      "令牌一旦签发就永久有效，降低了认证服务器的负载",
      "它实现了无状态认证，服务端无需保存会话信息，便于系统的水平扩展",
      "它提供了一种服务发现机制，能动态定位服务地址"
    ],
    "correctAnswerIndex": 2,
    "explanation": "JWT的核心优势在于其无状态性。令牌本身包含了用户的身份和权限等信息，并有数字签名。微服务收到请求后，只需在本地验证JWT的签名即可确认用户身份，无需查询数据库或中央认证服务器来维护会话状态。这极大地简化了架构，并使得服务可以轻松地进行水平扩展。",
    "source": "文档中「通信中的安全性」下的「JWT（JSON Web Token）」部分",
    "hint": "思考一下，“无状态”对于构建一个需要轻松扩展的分布式系统来说意味着什么。"
  },
  {
    "question": "文档中倡导的“零信任安全模型”的核心原则是什么？",
    "options": [
      "只要服务部署在公司内网，就可以相互信任",
      "默认不信任任何来源的请求，无论是来自内部网络还是外部网络，都必须经过严格的认证和授权",
      "通过加强网络边界防火墙来保护内部服务",
      "仅对来自外部客户端的请求进行安全校验"
    ],
    "correctAnswerIndex": 1,
    "explanation": "“零信任”模型颠覆了传统的“城堡-护城河”安全思想（即信任内网，防范外网）。它的核心原则是“从不信任，始终验证”，假设网络随时可能被攻破，因此每一次服务间的通信，无论其来源如何，都必须经过身份认证和权限校验，遵循最小权限原则。",
    "source": "文档中「通信中的安全性」下的「零信任安全模型」部分",
    "hint": "这个模型的名称本身就是一个强有力的提示：信任不是默认给予的。"
  }
];
        console.log("Quiz Data:", JSON.parse(JSON.stringify(quizData))); // 添加这行用于调试，以可展开的JSON格式输出
        
        let currentQuestionIndex = 0;
        let score = 0;
        // 存储每个问题的回答状态
        const userAnswers = new Array(quizData.length).fill(null); 

        const questionTextEl = document.getElementById('question-text');
        const optionsListEl = document.getElementById('options-list');
        const resultContainerEl = document.getElementById('result-container');
        const quizContentEl = document.getElementById('quiz-content');
        const progressIndicatorEl = document.getElementById('progress-indicator');
        const prevBtn = document.getElementById('prev-btn');
        const nextBtn = document.getElementById('next-btn');
        const hintBtn = document.getElementById('hint-btn');
        const hintContainerEl = document.getElementById('hint-container');

        function loadQuestion() {
          resultContainerEl.innerHTML = '';
          optionsListEl.innerHTML = '';
          hintContainerEl.style.display = 'none'; // 隐藏提示
          
          if (currentQuestionIndex >= quizData.length) {
            showFinalScore();
            return;
          }

          updateProgress();

          const currentQuestion = quizData[currentQuestionIndex];
          questionTextEl.textContent = `(${currentQuestionIndex + 1}/${quizData.length}) ${currentQuestion.question}`;
          
          currentQuestion.options.forEach((optionText, index) => {
            const li = document.createElement('li');
            li.className = 'option-item';
            li.textContent = optionText;
            li.dataset.index = index; // Store index in a data attribute
            // 如果这道题已经回答过，恢复状态
            if (userAnswers[currentQuestionIndex] !== null) {
                if (index === userAnswers[currentQuestionIndex]) {
                    li.classList.add('selected');
                }
            }
            optionsListEl.appendChild(li);
          });

          // 如果已经回答过，直接显示结果
          if (userAnswers[currentQuestionIndex] !== null) {
              const isCorrect = userAnswers[currentQuestionIndex] === currentQuestion.correctAnswerIndex;
              showResult(isCorrect, currentQuestion);
          }
          
          updateNavigationButtons();
          updateProgress();
        }

        function selectOption(optionIndex) {
            userAnswers[currentQuestionIndex] = optionIndex;
            const currentQuestion = quizData[currentQuestionIndex];
            const isCorrect = optionIndex === currentQuestion.correctAnswerIndex;

            // 重新计算分数
            score = userAnswers.reduce((acc, answer, index) => {
                return answer === quizData[index].correctAnswerIndex ? acc + 1 : acc;
            }, 0);

            showResult(isCorrect, currentQuestion);
            updateNavigationButtons();
        }
        
        function updateProgress() {
            const answeredQuestions = userAnswers.filter(answer => answer !== null).length;
            const progressPercentage = (answeredQuestions / quizData.length) * 100;
            progressIndicatorEl.style.width = `${progressPercentage}%`;
        }
        
        function updateNavigationButtons() {
            prevBtn.style.display = 'block';
            nextBtn.style.display = 'block';
            hintBtn.style.display = 'block'; // 显示提示按钮

            prevBtn.disabled = currentQuestionIndex === 0;
            nextBtn.disabled = false; // 最后一题时，下一题按钮不禁用，而是用于显示报告
            nextBtn.textContent = (currentQuestionIndex === quizData.length - 1) ? '查看报告' : '下一题';
            
            // 如果当前问题没有提示，则禁用提示按钮并隐藏提示内容
            if (!quizData[currentQuestionIndex].hint) {
                hintBtn.disabled = true;
                hintContainerEl.style.display = 'none';
                hintContainerEl.textContent = ''; // 清除旧的提示内容
            } else {
                hintBtn.disabled = false;
            }
        }

        function showResult(isCorrect, questionData) {
            resultContainerEl.innerHTML = ''; // 清空之前的结果
            const resultBox = document.createElement('div');
            resultBox.className = `result-box ${isCorrect ? 'correct' : 'incorrect'}`;
            
            let html = `<h3>${isCorrect ? '回答正确！' : '回答错误'}</h3>`;
            if (!isCorrect) {
                html += `<p><strong>正确答案是：</strong> ${questionData.options[questionData.correctAnswerIndex]}</p>`;
            }
            html += `<div class="explanation-text">${questionData.explanation}</div>`;
            html += `<div class="source-text">来源: ${questionData.source}</div>`;
            
            resultBox.innerHTML = html;
            resultContainerEl.appendChild(resultBox);

            // 禁用所有选项的点击事件，并高亮正确/错误答案
            Array.from(optionsListEl.children).forEach((child, index) => {
                child.style.pointerEvents = 'none';
                // 高亮正确答案
                if (index === questionData.correctAnswerIndex) {
                    child.classList.add('correct'); // 需要添加CSS样式
                    child.style.backgroundColor = '#d4edda';
                    child.style.borderColor = '#c3e6cb';
                }
                // 如果选错了，高亮错误选项
                if (!isCorrect && index === userAnswers[currentQuestionIndex]) {
                    child.classList.add('incorrect'); // 需要添加CSS样式
                    child.style.backgroundColor = '#f8d7da';
                    child.style.borderColor = '#f5c6cb';
                }
            });
        }

        function goToNextQuestion() {
            if (currentQuestionIndex < quizData.length - 1) {
                currentQuestionIndex++;
                loadQuestion();
            } else {
                showFinalScore();
            }
        }

        function goToPreviousQuestion() {
            if (currentQuestionIndex > 0) {
                currentQuestionIndex--;
                loadQuestion();
            }
        }
        
        function showHint() {
            const currentQuestion = quizData[currentQuestionIndex];
            if (currentQuestion.hint) {
                hintContainerEl.textContent = currentQuestion.hint;
                hintContainerEl.style.display = 'block';
            } else {
                hintContainerEl.style.display = 'none';
            }
        }

        function showFinalScore() {
            document.querySelector('.quiz-body').style.display = 'none';
            document.getElementById('quiz-footer').style.display = 'none';

            const correctCount = score;
            const totalQuestions = quizData.length;
            const answeredCount = userAnswers.filter(a => a !== null).length;
            const wrongCount = answeredCount - correctCount;
            const skippedCount = totalQuestions - answeredCount;
            const accuracy = totalQuestions > 0 ? Math.round((correctCount / totalQuestions) * 100) : 0;
            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

            const finalScoreHtml =
                '<div class="final-score-container">' +
                '<h2>答题报告</h2>' +
                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  